It is a fringe of tissue with an opening, present from birth.
The hymen is a thin rim of tissue at the vaginal opening, and in almost every person it has an opening from birth — otherwise menstrual blood would have nowhere to go. It does not cover anything, so there is nothing to break. It can stretch, and it can tear, and in many people it does neither noticeably.
Studies of adolescents who had had intercourse found that around half had no detectable change to the hymen at all. This is why every major medical body states that a physical examination cannot establish whether someone has had sex — a conclusion the World Health Organization used in 2018 to call for so-called virginity testing to be banned outright.
